Repair a Crumbling Brick Chimney

Get tips on sealing and repairing a crumbling brick chimney. Find out what product to use to repair the brick, and learn what to put on the brick to prevent future crumbling problems, as well as what to do to protect the chimney from inclement weather.

LESLIE: Tom in Georgia has a home where the brick is breaking off, if you will. Welcome, Tom. How can we help you?

TOM IN GEORGIA: Oh, how you doing? I just bought an older home and it’s got a nice, brick fireplace but the chimney[1] that’s exposed on the roof is crumbling a little bit and there are actually pieces of it on the roof. And I’m trying to find out what I can do to seal it to keep it from further crumbling. I’m assuming it’s doing it from the heat and the cold and just being old brick.

TOM: Yeah, well the frost cycle definitely causes some problems. What you’re going to want to do is repair all those spawled areas. Now, you can do it with an epoxy patching compound; although I will say that it’s going to be difficult to have it match. You can actually add colorants to epoxy products so you get something that’s similar to brick color and perhaps from the street you can almost have it not be that totally visible. But what you don’t want to use is use anything that’s just a straight concrete type of a mix or mortar type of mix because it will fall right off.

TOM IN GEORGIA: Right. Is there anything that I can apply to the brick to keep it from further crumbling after I do the repair you’ve described?

TOM: Right, once you repair the deteriorated brick, here’s what you want to do. Look at the chimney crown; that’s the upper surface of the chimney. There are probably going to be some cracks in that between the flue line around the edge of the chimney and that’s where water gets in, gets the brick real wet and then it freezes and then it deteriorates. So you want to make sure the chimney crown is in good shape and you almost might want to consider putting a cap on the chimney. And if you can keep the weather from getting in around the top, that protects the brick.